Drill

Abstract

A drill for forming bores in constructional components and including a tubular stem (2; 22; 32; 42) having an axially extending through-channel (3; 23; 33; 43) which opens into at least one suction opening (7; 11; 27; 37; 47), a shank (5) provided at a rear end of the stem for connecting the drill to a drilling tool (M), and a drilling head (8; 28; 38; 48) having lips (9; 29; 39; 49) and formed entirely of a cutting material and substantially butt-joined to the stem (2; 22; 32; 42) at a free front end of the stem (2; 22; 32; 42), with at least one suction opening being formed by a mouth opening of a front channel (12; 26; 36; 46) which is limited, at least partially by a material of the drilling head (8; 28; 38; 48) and a mouth surface of which, at least partially is arranged in a circumferential region of at least one of the stem (2; 22; 32; 42) and the drilling head (8; 28; 38; 48).

What is claimed is: 
     
       1. A drill for forming bores in constructional components, comprising a tubular stem (2; 22; 32; 42) having an axially extending through-channel (3; 23; 33; 43) which opens into at least one suction opening (7; 11; 27; 37; 47); a shank (5) provided at a rear end of the stem for connecting the drill to a drilling tool (M); and a drilling head (8; 28; 38; 48) having lips (9; 29; 39; 49) and formed entirely of a cutting material and substantially butt-joined to the stem (2; 22; 32; 42) at a free front end of the stem (2; 22; 32; 42), the at least one suction opening being formed by a mouth opening of a front channel (12; 26; 36; 46) which is limited, at least partially by a material of the drilling head (8; 28; 38; 48) and a mouth surface of which, at least partially is arranged in a circumferential region of at least one of the stem (2; 22; 32; 42) and the drilling head (8; 28; 38; 48). 
     
     
       2. A drill according to claim 1, wherein the drilling head is formed of the hard metal and is one of welded and soldered to the stem (2; 22; 32; 42). 
     
     
       3. A drill according to claim 1, wherein more than two-thirds of the mouth surface of the front channel (12; 26; 36; 46) is arranged in the circumferential region of the at least one of the stem (2; 22; 32; 42) and the drilling head (8; 28; 38; 48). 
     
     
       4. A drill according to claim 1, wherein the front channel (12; 26) is oriented in a direction toward one of an outer surface of the stem (2; 22) and an axial side surface (10, 25) of the drilling head (8; 28) and forms with a axis (A) of the stem (2; 22) an angle (α) which is smaller than 90°. 
     
     
       5. A drill according to claim 4, wherein the front channel (12; 26) forms with the axis (A) of the stem (2; 22) an angle (α) which lies in a range from 10° to 70°. 
     
     
       6. A drill according to claim 1, wherein the mouth opening of the front channel (10) has a cross-section which is smaller than a cross-section of the through-channel (3; 23; 33; 43). 
     
     
       7. A drill according to claim 6, wherein the cross-section of the mouth opening (10) amounts to from 30% to 70% of the cross-section of the through-channel (3; 23; 33; 43). 
     
     
       8. A drill according to claim 1, wherein at least one of the front channel and the through-channel of the stem has a non-circular cross-section. 
     
     
       9. A drill according to claim 1, wherein the stem (22; 32; 42) has non-circular circumferential contour. 
     
     
       10. A drill according to claim 1, wherein the through channel (23) has, at least in a front section of the stem (22) a polygonal cross-section, and the drilling head (28) has, at an end thereof opposite the lips (29) an axial extension (24) the circumferential contour of which corresponds, at least regionwise to the cross-section of the through-channel (23), whereby the drilling head extension (24) is retained in the through-channel (23) without a possibility of rotation relative thereto. 
     
     
       11. A drill according to claim 1, comprising a plurality of suction openings (37; 47) a number of which corresponds to a number of the lips (39, 49) provided on the drilling head, and wherein an angular distance between a leading, in a rotational direction, lip and an immediately trailing it, suction opening is less than 90°. 
     
     
       12. A drill according to claim 1, wherein the drilling head (38; 48) has three lips (39, 49) angularly spaced from each other by an angle lying in a range from about 90° to about 180°. 
     
     
       13. A drill according to claim 12, wherein the three lips (39; 49) are angularly spaced from each other by an angle of 120°. 
     
     
       14. A drill according to claim 12, wherein the stem (42) has, at least in a front section thereof, a polygonal contour, and wherein the drilling head (48) has a lip-supporting widened head base (50) having side surfaces (51) which coincide with outer surfaces of the stem (42), the lips (49) forming with the side surfaces (51) of the head base (50) an angle of about 90°±10°.